The invention relates to atomizing nozzles and devices which dispense fluids in a misted or dispersed, small particle size, form. Certain devices constructed according to the instant invention are particularly suitable for use in pulmonary therapy. The invention also relates to atomizers having a one-way valve to resist leakage of pre-loaded fluids and nozzle dribble subsequent to a fluid discharge.
Atomizing nozzles are used for delivery of fluids, including medications, in a dispersed, or misted, form to both external and internal surface areas of a subject. A range of typical commercially available atomizing nozzles and atomizer assemblies are manufactured by Valois S.A., a French Company having a head office located at Rue Du Doyen, Jussiaume, 27110 Le Neubourg France.
Available atomizing nozzle assemblies typically have an atomizer nozzle attached to an elongate member to dispense the atomized fluid at a distance from a pressurized fluid source. A pressurizable source of medication or other fluids is either affixed or attachable to an opposite end of the elongate member. Many atomizer nozzles are sized to resist insertion of a nozzle tip too far into an orifice, such as a nostril. In use of such atomizer assemblies in pulmonary therapy, the nozzle tip may be inserted into an endotracheal tube, and the medication dispensed. Even presupposing that the nozzle itself fits within the endotracheal tube, the length of the elongate member of commercially available atomizer assemblies is less than the length of typical endotracheal tubes. Therefore, the atomized fluid unavoidably is dispensed into contact with the interior of the endotracheal tube. Droplets form on the tube wall and drip into the bronchial area of a subject, causing a gag reflex which may cause the subject to expel an indeterminate quantity of the medication though the endotracheal tube. In such case, the endotracheal tube effectively becomes a discharge nozzle, potentially dowsing medical personnel with disease bearing medication and body fluids. Besides a gag incident being uncomfortable to the subject, medical personnel are placed at risk of infection. Furthermore, the medication dose received by a subject is unreliable subsequent to a gag incident, potentially contributing to either an over- or under-medicated state in the subject.
Syringes are relatively inexpensive and capable of generating high pressures on selectable volumes of medication fluids. A syringe may be pre-filled with a desired medication dose, and attached to an atomizing nozzle. Subsequent to such attachment, it is desirable that the medication fluid not leak out of the nozzle orifice during storage prior to being dispensed. Prevention of such fluid leakage helps to maintain a sterile field about a subject. Puddles of medication fluid that has leaked from an atomizer may undesirably contaminate other instruments. Furthermore, a leaking atomizer may contain an unknown dose amount, or an undesirably small dose amount, when the medication fluid finally is dispensed.
U.S. Pat. No. 5,601,077 to Imbert discloses a one-way valve to resist leaking from a loaded syringe attached to an atomizer nozzle. The valve member is a piston-like element slidably disposed in a bore and having a wiping lip arranged as a cylindrical skirt to seal against the bore wall. The seal is adapted to deflect radially to permit fluid flow in one direction. The radial motion required by such a valve member essentially limits the extent to which a diameter of the valve may be reduced. Imbert""s teachings are directed to large diameter atomizers used for nasal treatment, and as such, are not well suited to application for pulmonary therapy. In application of Imbert""s devices to pulmonary therapy, an undesirably large amount of atomized fluid inherently would be deposited onto the bore of an endotracheal tube, with the resulting drops of medication contributing to causing a gag reflex in a subject. Improvements to atomizers such as Imbert""s device are desired to form a device compatible with insertion into an endotracheal tube, to reduce complexity in constituent element conformation, and to provide additional dribble control.
It is desirable for an atomizer nozzle to provide a clean and dry exterior surface at its discharge end subsequent to dispensing a quantity of a medication fluid. Commercially available atomizer nozzles commonly leave a partial drop at the nozzle discharge orifice which may subsequently dribble from the orifice and undesirably wet the nozzle exterior. A protruding partial drop or a wetted nozzle exterior may undesirably transfer medication to unintended locations, including to medical personnel. The elimination of such a dribble phenomena would be an improvement to medical atomizers.
The invention may be embodied as an improved atomizer assembly for delivery of fluids, substantially as a mist, to an area. A preferred embodiment delivers atomized medications to a pulmonary area of a subject. Such a pulmonary atomizer assembly may include an atomizing nozzle having a body with a diameter sized to fit within an endotracheal tube, and a tip with a discharge orifice. The nozzle body is typically attached to a first end of an elongate tubular member, which carries a second conduit for delivery of fluids from a pressurizable fluid source. Connection structure affixed at a second end of the tubular member is generally adapted to connect the pressurizable source of fluids into fluid communication with the nozzle discharge orifice. Elongate members used in pulmonary atomizer assemblies desirably have a length sufficient to enable extending the nozzle tip to a distal position for discharge of fluids external to the endotracheal tube to reduce droplet formation on the endotracheal tube walls. Droplets formed on the endotracheal tube may drip into the bronchial area, and cause a gag reflex in a treated subject.
One preferred pulmonary atomizer has an elongate member with a length longer than about 14 inches. A suitable elongate member may be made from medical grade tubing having a diameter of about xe2x85x9 inches. Sometimes an elongate member includes a plurality of internal conduits. In such case, a malleable wire disposed in one of the conduits can function deformably to hold a shape in the elongate member. Indicia visible on the elongate member can assist to indicate the relative position of the nozzle with respect to a distal end of an endotracheal tube installed in a subject.
The pulmonary atomizer assembly can include a branched adapter structured and arranged at a stem opening for connection to a proximal end of an endotracheal tube. The elongate member is desirably slidably extendable through a first branch opening in the branched adapter. A pulmonary assembly may also include a cap disposed at an opening of the branch housing the elongate member. In such a case, the cap can provide a wiping seal to a surface of the elongate member.
A first type of desirable atomizer nozzle for use in the pulmonary atomizer assembly has a nozzle body shaped somewhat like a thimble. The thimble provides structure at a distal interior end which defines a forward portion of a swirling chamber having inlet ports and an exit orifice. A rear portion of the swirling chamber is defined by a wetted portion of the distal end of a plug. The plug may also serve as a one-way valve member. The plug is typically deformed under an assembled self-bias such that a proximal end of the plug occludes an inlet at a distal end of the elongate member and thereby resists inadvertent discharge of a fluid from the fluid source. Deliberate pressurization of the fluid, above a certain threshold value, causes the plug to deflect sufficiently to permit discharge of fluid through the atomizer nozzle. Such a valve may permit storage of pre-loaded medications in a device without risk of medications leaking through the nozzle. In one embodiment, a threshold pressure is about 5 psi. A proximal end of the nozzle body is typically constructed and arranged for connection to the end of the elongate member.
The one-way valve can function to resist nozzle dribble. Nozzle dribble may be defined as a remnant drop, or partial drop, remaining at the distal end of an atomizing nozzle subsequent to operation of the atomizer. In such a case, the drop may flow and wet the nozzle tip, or simply protrude from the nozzle body. In either case, the exposed fluid may potentially be transferred inadvertently to undesired locations. Recall that the plug is received within a bore in the nozzle body. The plug assumes a first deformed configuration during assembly of a nozzle body to an elongate member; assumes a second deformed configuration when fluid is forced under pressure past the plug for discharge through an exit orifice; and returns to the first deformed configuration when pressure is sufficiently reduced on the fluid. Movement of the plug from the second to the first deformed configuration can retract fluid at the exit orifice back into the interior of the nozzle, whereby to help maintain a dry nozzle tip exterior. Alternatively, momentum of the fluid adjacent the nozzle distal tip can help to evacuate the distal portion of a plug chamber subsequent to the valve closing.
A second type of desirable atomizer nozzle for use in the pulmonary atomizer assembly has a tip member with at least one standoff and a surface defining a forward portion of a swirling chamber having at least one turbine port and an exit orifice. The second nozzle further typically includes a one-piece body forming a conduit for fluid communication between distal and proximal body ends. The distal end houses a post having a distal post surface configured to contact the standoff(s). A wetted portion of the post end surface also defines a rear of the swirling chamber. The second nozzle may include a plurality of standoffs, with the standoffs functioning to space apart a plurality of turbine ports. One exemplary embodiment of this type has three standoffs spacing apart 3 turbine ports.
Both types of nozzle assemblies may benefit from a fluid ring being disposed upstream of the turbine inlet ports to promote uniform fluid flow into the turbine ports. Additionally, both types of atomizer nozzles can be used in non-pulmonary therapy environments. One use for embodiments having a one-way check valve may be as atomizer assemblies which can be stored pre-loaded with vaccines for nasal treatments.